Door closer

ABSTRACT

A door closer comprises a torsion spring effecting to rotate a door in the closing direction, a brake drum rotating together with rotation of the door, and at least two relative brake shoe units provided at the position of inserting the brake drum for preventing rotation of the brake drum and reducing a closing speed of the door and for frictionally and resiliently pressing brake surfaces of the brake drum, respectively.

[ 1 Dec. 18, 1973 Forth.......................

Mallory............ Shackleton et al. 8/1946 Denmark......

ABSTRACT FOREIGN PATENTS OR APPLlCATlONS 6 Claims, 12 Drawing Figures Primary Examiner-James T. McCall Assistant ExaminerPeter A. Aschenbrenner AtwrneyRobrt E. Burns A door closer comprises a torsion spring effecting to rotate a door in the closing direction, a brake drum rotating together with rotation of the door, and at least two relative brake shoe units provided at the position of inserting the brake drum for preventing rotation of the brake drum and reducing a closing speed of the door and for frictionally and resiliently pressing brake surfaces of the brake drum, respectively.

Yoshitaka Nakanishi, 12-9, S-chome Yawata, lchikawa, Japan Filed: Nov. 15, 1971 App]. No.: 198,709

Foreign Application Priority Data Nov. 20, 1970 Field of Search References Cited UNITED STATES PATENTS United States Patent Nakanishi 1 DOOR CLOSER [76] Inventor:

0 4A A m 4 7 97 3 J 4 6 dA/l/ M1 AM/EW/ *7 5 2 2 4 5K! w m e 1 9 5 PATENIEDUEE 18 I975 SHEET 4 CF 5 FIG.9

FIG.8

,FIGJQ DOOR CLOSER The present invention relates to a door closer, more particularly to a novel and improved product or device for controlling and decelerating a return speed of a door closed by a spring by means of a mechanically frictional brake.

A door closer, which return speed is decelerated by inserting a piston into a cylinder, controlling the moving speed of the piston by utilizing a fluid such as air or oil, thereby lowering the speed, has publicly been known, and many of such door closers are practically used at present. However, the door closer with the use of such fluid causes difference in the decelerating action by a temperature change of the open air or trouble in the decelerating action by leakage of the fluid. Further, there is required high precision of size between the cylinder and the piston and a valve mechanism, while it is generally large-sized from the limit of efficiency thereof and production cost becomes high. Further, such large-sized appearance is an offense to the eye.

Different from the above type, there is also wellknown a door check or a door closer having a frictional brake means.

However, these door checks or door closers are no better than a mere proposal nor completed for starting them into a commercial base, so that it is difficult to find any sample thereof in the market. It can easily be conceived that the checking action cannot properly and smoothly be actuated and it does not pay due to a short life of durability and complicated structure.

An object of the present invention is to provide a door closer which return speed actuated in the closing direction by a spring is controlled by a proper mechanically frictional brake action. Further, the efficiency of the door closer according to the present invention is excellent, the door can quietly be returned, the fastening of the door can be maintained with durability, and the structure thereof is very simple and compact, so that the present door closer can easily and economically be produced and the processing thereof is also possible, and the device, article and member having good appearance can be provided.

According to the present invention, the device and parts having the above-mentioned charming properties can be obtained. Further, the member also contains characteristics, which will be explained later.

In order to attain the above-mentioned various objects, the door closer comprises a torsion spring for rotating the door in the closing direction and a brake drum which rotates in proportion to rotation of the door, wherein the brake drum is coupled to the torsion spring and rotated by interlocking with a shaft rotated in the closing direction, so as to prevent rotation of the brake drum and to decelerate the closing speed'of the door, thus the shaft is arranged at the position for inserting the brake drum, and at least two brake shoe units are provided on brake surfaces of the brake drum, respectively.

The brake drum and brake shoe are made of elastic material and as an elastic material plastics is used.

In the present invention, the door check device containing the brake drum and a special brake drum itself are provided. I

In such a brake drum, there is one which main body is substantially solid or the other one which main body has an annular groove.

The brake drum having an annular groove can be annular-intermittent, but it will form a space region and such space region can be utilized for the brake action and the means for maintaining a compression spring for pressing the brake drum to the other, which will be explained later.

Other objects and advantages of the invention and details of construction of a preferred embodiment will be apparent from the following description with reference to the drawings in which FIG. 1 is a perspective view of the door closer according to the present invention;

FIG. 2 is a plan view of the door closer without an upper cover plate and an arm;

FIG. 3 is a bottom view of the door closer without a lower cover plate and an arm;

FIG. 4 is a vertical cross-sectional view of the door closer along the line IV-IV of FIG. 2, partly cut off;

FIG. 5 is a longitudinal cross-sectional view of the door closer along the line V-V of FIG. 4;

FIG. 6 is a vertical cross-sectional view of the door closer along the line VI-VI of FIG. 4, partly cut off;

FIG. 7 is a perspective view of a brake drum, a brake shoe and a brake disk;

FIG. 8 is a perspective view of the brake drum viewed from the lower part thereof;

FIG. 9 is a perspective view of the brake viewed from the lower part thereof;

FIG. 10 is a perspective view of a rotor and a lining;

FIG. 11 is a vertical cross-sectional view showing a modification of FIG. 4; and

FIG. l2-is a perspective view showing another embodiment of the brake drum.

In FIGS. 1 to 4, a case 1 is secured to the door (not shown) by means of a bracket 2 elongated to both sides thereof. In the case a shaft 3 is rotatably supported. The shaft 3 is actuated in accordance with rotation of the door secured through arms 5 6 and a bracket 7.

The case 1 is formed in a horizontally square shape with outer walls 8 9 l0 and 11 on every outer sides, but upper and lower sides are opened and separated into an upper chamber 13 and a lower chamber 14 by a partition 12 provided in the middle. At the central portion of the partition there is a hole 15 where the shaft 3 is freely disposed and a cylinder 16 through the hole is'extended from the partition to downwards.

The shaft 3 is square-shaped in cross section, provided with an annular groove 17 at optional position, and supported with the partition 12 by engaging a stop ring 18 having a C-shape engaged to the groove to the periphery of the hole 15 of the partition.

A brake disk 19 is mounted on the upper surface of the partition 12 in the state of freely inserting the shaft 3 in a hole 19a of the disk and inserting the C-ring '18 therebetween, and tightly secured to the partition by means of a screw 22 screwed in a screw hole of the partition 12 from the peripheral hole. By providing the stop ring 18 between the brake disk 19 and the partition 12, the shaft 3 cannot be moved tion but only rotated.

A space 23 is provided between the shaft 3 and the cylinder 16 and a torsion spring 24 is inserted between the space. One of ends of the torsion spring is inserted in a hole 26 of the partition 12 and in a hole 29 of a rotor 28 is inserted the other end 27, thereby controlling the action of the door correlatively moving with the other mechanism and means through the rotor. The

in the axial direcrotor 28 is inserted in the cylinder 16 so as to be rotated by rotation of the shaft 3, and supported by a cover plate 30. This cover plate 30 is secured to a back wall 1 l by means of a bracket 31 13 bent at right angles at one side and a screw 32.

Particularly, in FIGS. 3 to and FIG. 10, a projection 34 having engaging surfaces 34a 34b is extended from the outer periphery of the rotor 28, so as to swing between both the front and rear wall surfaces 8 l1 faced to the outward from a recess portion 35 at a lower end of the cylinder 16. Thereby, when the door is at the closed position, the engaging surface 34a of the projection 34 is attached to the inner surface of the front wall 8, the rotor 28 is rotated in the direction of an arrow A, together with the shaft 3 as the door opens, the engaging surface 34b is contacted to the inner surface of the rear wall 10, and rotation of the door is stopped. In this case, the door is stopped at the position at the maximum open position, but not more. As the shaft 3 is rotated in the direction opened to in which the door is opened, the torsion spring 24 is twisted through the rotor 28, the shaft 3 is rotated in the direction for closing the door by this torsional energy, and the door is automatically closed.

Moreover, there are a plurality of holes 29 of the rotor, and by inserting one end 27 of the spring 24 into either one of these holes, the torsional force of the torsion spring can be adjusted. Around the outer periphery of the rotor is applied a plastic lining 36 for suitably contacting it to the cylinder 16. The lining 36, as shown in FIG. 10, has a frictional portion 36a covering the outer periphery of the rotor and a flange portion 36b covering the upper surface of the rotor, and then a recess portion 360 of the frictional portion is engaged across the projection 34, so as to prevent a relative slip of the rotor 28 with the lining 36. On the rotor 28 and the partition 12 are extended arc-shaped walls 28a 28b, respectively, and these walls are in the state of contacting to the inner surface of the spring 24 to equally twist the spring 24.

Further, refer to FIGS. 7 to 8. At the portion extended to the upper part of the partition 12 is relatively rotated the brake drum 37 with the shaft and slidably engaged in the axial direction.

The brake drum 37 has an annular groove 38 which upper surface is opened, and a coil spring 39 is provided in the groove. At the upper portion of the brake drum is provided a disk 40 which is not relatively rotated with the shaft 30 and slidably moved in the axial direction, thereby the spring 39 is sealed in the annular groove 38. A cover plate 41 is secured to the rear wall 11 of the case by the rear peripheral brackets 42 42 and the screw 43 in the same manner with the cover plate 30 of the lower part, theupper opening of the case 1 is closed, and the upper end of the shaft 3 is extended upwards from the central hole 44.

The brake drum 37 and the disk 40 have the same diameter, are contacted with both the front and rear wall surfaces 8 11, and the contact surface 45 of both the wall surfaces is formed by the same are surface with the outer peripheries of the brake drum 37 and the disk 40, so that the brake drum 37 and the disk 40 are supported to allow rotation only without moving to all sides by both the walls 8 11. Accordingly, the shaft 3 integrally connected with the brake drum 37 is rotated on the concentric axis.

The lower surface of the brake drum 37 is superposed on the surface of the brake disk 19 and pressed by the spring 39.

The brake disk 19 is formed proper uneven surfaces, e.g., convex portions radially extended from the center, on the upper surface, while concave surfaces 63a are formed by these convex portions. Further, on the lower surface of the brake drum 37 are formed radially uneven portions 64, 640 which engage the convex portion 63 with the concave portion 63a, thereby a braking force becomes large.

A brake shoe unit 46 has a concave surface 50 by corresponding to the brake drum and the concave surface is contacted to the brake drum for braking the rotation of the drum.

On the rear faces of the brake shoe unit are extended vertical pieces 51, respectively, both ends 52 52 of the vertical pieces are slidably contacted to the inner surfaces of the cover 41 and the partition 12, and both the side surfaces 53 are slidably contacted to the inner surfaces of the front and rear walls 8 11, and along these inner surfaces the sliding of each brake shoe unit can be allowed to both sides at the proper condition.

In the spaces between each brake shoe unit and both the right and left walls 9 and 10 are provided springs 47, respectively, and the brake shoe is pressed to the brake drum by the spring.

As the plurality of brake shoe units press the brake drum from both sides, the shaft secured with the brake drum is maintained at the straight position, so that the braking force can be made larger, and the shaft is smoothly rotated even if the structure of the supporting means of the shaft is simplified. Further, each spring force can be minimized by despersing the braking force, so that minimization of the device and easy assmebly of the spring can be brought. Further, the wear of the brake drum and the brake shoe units can be lessened.

In order to control the compression strength of the spring 47, the following means can be adopted.

A square plate 54 is provided between one end of the spring 47 and the inner surfaces of both the side walls 9 l, a projection 55 projected on the inner surface of the plate is extended in the spring 47, a recess 56 is formed on the outer surface of the plate corresponding to the projection, and one end of a screw 57 is inserted into the recess. The screw is secured into screw holes of both side walls 9 and 10 of the case, and the plate is moved to both sides by rotating the screw to either side of the right or left.

As the brake drum 37 has the annular groove 38, the followings are liable to cause. One of them is, in case of pressing the brake surface of the brake drum by the brake shoe units from both sides, to cause deformation of the brake drum by compressed in the direction of its pressing force and elongated to the lateral directions, i.e., an oval. Here, with rotation of the brake drum the phenomenon of the compression and elongation along the outer periphery is alternatively repeated. Such deformation is actuated for preventing rotation of the brake drum and the whole braking force becomes larger by adding the frictional resistance-thereto. The other one of them is to shortin the height of the case in proportion to the length of the portion where the spring 39 is inserted, into the annular groove 38 of the brake drum, so that it brings minimization of the whole device. Accompanied with these, the spring 39 is stably supported by entering into the manner groove.

As an example of transformation of the brake drum, there is one having the uneven surface on the outer pe riphery thereof. 1

On this uneven surface are provided a knurl 62 and a pattern 63d. (FIG. 7). These uneven surfaces are applied on the whole periphery of the body of the drum (not shown) or applied thereon partially.

The partially uneven surface can be formed at a special position or in a special configuration. That is, the partially uneven surface is, when the door is at the opened position, contacted or not contacted with the brake surface of the brake shoe, and in accordance with rotation of the door in the closing direction it is strongly contacted with the brake surface of the shoe. Such means strengthens the essential action of the brake means.

As another modification of the brake drum, the drum may be made of materials consisting of acetal resin or polyamide resin, to which is mixed asbestos powder. For instance, there is a material made by mixing 100 parts by weight of Duracon (Trademark of Cellanese Co., in the U.S.A.) with asbestos powder at the ratio of 10-45 parts by weight. The brake drum made by the material has rich durability, large friction coefficient and rigidity which is lacked in the other plastic materials, further the brake drum has less creep amount and low hygroscopicity. Accordingly, there is no excess slip and proper friction coactuating with rigidity, so as to bring the preferable brake action which cannot be obtained from the brake means of a preceding piston type. This asbestos powder is successively thrusted on the surface of the drum, even if the plastic material which is mixed with is reduced, and makes rigidity, friction and the like of the drum almost unchangeable.

Further, the asbestos powder gives thermal resistance to the drum so as to avoid thermal expansion and thermal strain which cause at the time of friction. Besides Duracon, nylon is also preferably used.

It is preferable to form the brake disk and brake shoe with the same material as well as the brake drum. Further, with the use of the same material, the function of the above-mentioned brake drum is accelerated and stability of the convex portion which is liable to be broken is increased.

This device is constructed by the means and members and both ends of the shaft extending above and below; therefore, it can be applied at either side by simply turning it upside down. In this case, the end portion which shaft is not used is covered with a cap 70 (for instance, made of synthetic resin). A hook 71 is projected at an opening periphery of the cap and hooked to the hole 33 of the cover plate.

FIG. 11 is referred. According to the modification, the spring 39 is provided at the lower portion of the brake disk 19 instead of pressing the brake drum downwardly, and applied to press it at the brake drum side. In this case, a cylinder 65 is provided in the cylinder 16. The cylinder 65 is extended downwardly from the partition 12, the spring is provided in a space 67 between the cylinder 65 and the shaft 3, and the spring is supported by a flange 66 provided at the lower end of the cylinder. The C-ring 18 is engaged with the groove 17 of the shaft between the flange and the spring.

Instead of a screw stopper of the brake disk, the projection 68 is extended to the lower surface of the disk,

the projection is inserted into a hole 69 of the partition, and it does not make rotation of the brake disk but makes possible to move it to the axial direction.

The case 1, the partition 12 and the cylinders 16 65 are integrally formed in one frame by a die cast method, but it is also possible to form each member separately and to assemble them with screws or the like.

It has already been described that such frame and each member are independently formed and easily assembled with each other.

When the device is secured and the door is opened, the shaft 3 is rotated through the arms 5 6 and the torsion spring 24 is twisted, this twist or force developed is stored for closing the door, and the thus opened door is biased to the closing direction.

As the door closes, the brake drum and the brake shoe unit coact with the brake drum from the directions of both sides can check whether or not the door is slammed. Further, according to the present device, the door can smoothly and quietly be closed with the aid of friction of the brake members from both sides, spring pressure, friction of the brake members in the vertical, i.e., axial direction, spring pressure and the like.

Despite some example of embodiment as described above, it is clear that the present invention is not to be limited to these examples of application, but can be variously modified within the scope of the sprit of invention indicated in the patent claims.

What is claimed is:

l. A door closing and checking device comprising, a rotary spindle rotatable in opposite directions, means connected to said spindle for connection to a door to be closed and checked, means comprising a torsion spring circumferentially of said spindle for developing and storing energy during opening of the door and applying a biasing force to said spindle in a direction for closing said door, a brake drum circumferentially of said spindle coaxial with said torsion spring, means connecting the brake drum to said spindle for rotation therewith, a plurality of arcuate brake shoes biased into engagement with said brake drum peripherally thereof when said drum rotates in a direction corresponding to the direction of rotation when said door is being closed, a friction brake member coaxial with drum, spring means biasing the drum axially into frictional contact with said friction brake member coacting with said brake shoes in braking the rotation of said brake drum.

2. A door closing and checking device according to claim 1, in which said brake drum comprises external surfaces having different coefficients of friction engaged by said shoes, said surfaces comprising surfaces of greater friction engaged by said shoes as said drum rotates in a direction corresponding to a direction of rotation when the door is being closed.

3. A door closing and checking device according to claim 2, in which said surfaces having a greater friction comprise knurled surfaces.

4. A door closing and checking device according to claim 1, in which a friction brake member is disposed circumferentially of said spindle, and in which said spring means is disposed internally of said brake drum.

5. A door closing and checking device according to claim 1, including a rotor circumferentially of said spindle and rotatable therewith, said rotor being disposed coaxial with said torsion spring, means on said rotor for connecting the torsion spring and rotor for variable adjustment of the torsion force developed by said spring when said door is opened.

6. A door closing and checking device according to compartments, said spring means and rotor being disposed in one of said compartments and said friction member and rotor being disposed in the other of said claim 5, including a casing having a first and a second compartmentscompartment, said spindle extending axially into said 

1. A door closing and checking device comprising, a rotary spindle rotatable in opposite directions, means connected to said spindle for connection to a door to be closed and checked, means comprising a torsion spring circumferentiAlly of said spindle for developing and storing energy during opening of the door and applying a biasing force to said spindle in a direction for closing said door, a brake drum circumferentially of said spindle coaxial with said torsion spring, means connecting the brake drum to said spindle for rotation therewith, a plurality of arcuate brake shoes biased into engagement with said brake drum peripherally thereof when said drum rotates in a direction corresponding to the direction of rotation when said door is being closed, a friction brake member coaxial with drum, spring means biasing the drum axially into frictional contact with said friction brake member coacting with said brake shoes in braking the rotation of said brake drum.
 2. A door closing and checking device according to claim 1, in which said brake drum comprises external surfaces having different coefficients of friction engaged by said shoes, said surfaces comprising surfaces of greater friction engaged by said shoes as said drum rotates in a direction corresponding to a direction of rotation when the door is being closed.
 3. A door closing and checking device according to claim 2, in which said surfaces having a greater friction comprise knurled surfaces.
 4. A door closing and checking device according to claim 1, in which a friction brake member is disposed circumferentially of said spindle, and in which said spring means is disposed internally of said brake drum.
 5. A door closing and checking device according to claim 1, including a rotor circumferentially of said spindle and rotatable therewith, said rotor being disposed coaxial with said torsion spring, means on said rotor for connecting the torsion spring and rotor for variable adjustment of the torsion force developed by said spring when said door is opened.
 6. A door closing and checking device according to claim 5, including a casing having a first and a second compartment, said spindle extending axially into said compartments, said spring means and rotor being disposed in one of said compartments and said friction member and rotor being disposed in the other of said compartments. 